1. Technical Field
This invention relates generally to the field of sealing thermal expansion gaps between adjacent monolothic structures and specifically to expansion joints for sealing expansion gaps of roadways, bridge decks, parking garages and the like.
2. Background Art
U.S. Pat. No. 3,363,383 to La Barge discloses an expansion joint structure for sealing vertical seams between adjacent building panels rather than for tire contacting bridge or highway service. The combined securing and sealing member is resiliently deformed for securing in the mounting recess which is normally adequate for the intended static structural use or service.
U.S. Pat. No. 2,796,624 to Speer discloses an expansion joint for use with a linoleum floor covering while U.S. Pat. No. 4,067,155 to Ruff, et al. discloses a thermal and moisture resistant seal for gaps between structural building panels. The seal of the latter patent employs both interfitting resilient teeth and an adhesive-sealant that seals the secured cap to the adjoining panels.
Brown U.S. Pat. No. 4,007,994 is entitled "Expansion Joint With Elastomer Seal" and discloses a V-shaped elastomer seal of neoprene formulation is secured by resilient elongated tongue and groove means which are deformingly received in recesses formed in the extruded aluminum longitudinal side frames. The Brown expansion joint is intended for use on pavements and bridge decks as is a similar joint disclosed in companion Brown U.S. Pat. No. 4,063,839.
U.S. Pat. No. 3,606,826 to Bowman discloses an expansion joint having a unitary tubular resilient sealing member having an internal truss structure which mechanically interlocks with the two parallel support frame members to minimize tensile strain on the adhesive bonding. The expansible and contractable seal may be employed in either a single or double mounting depending on the width of the gap. In the double mounting, a metal wear tread member is secured to the floating central connecting member for bridging the gap to protect the seal.
U.S. Pat. No. 3,595,142 to Via is entitled "Expansion Rubber Joint For Roads And Bridges". The disclosed expansion joint seal strip is provided with two parallel beads each having a half dove-tail fit for mechanically securing in complementary grooves in the adjacent sections. Resilient wedge members secure the elongated seal in each of the grooves or channels to prevent puckering of the seal edges when under tire traction.
Sequarius U.S. Pat. No. 3,520,236 is entitled "Means For Covering And Rendering Waterproof Expansion Joints For Road, Bridges And Other Civil Engineering Constructions". The disclosed seal employs an elastic strip secured in position by suitable bolting. The Leavy elastomer seal mounts a metal stiffener or reinforcing plate which slides on a metal support plate that bridges the gap to support the seal.
U.S. Pat. No. 4,285,612 to Betti utilizes an epoxy mortar to cast shoulders of the concrete joint adjacent the gap for strengthening the edges of the concrete panels. The gap or socket formed between the shoulder receives a hollow resilient sealing element which is secured by an adhesive to the shoulders. The hollow core of the element is then filled with a pressurized liquid filler material that hardens or sets after the adhesive bonds the sealing element to both shoulders.
In Puccio U.S. Pat. No. 4,378,176 snow plow deflectors are provided for the resilient roadway expansion joint seal which is secured by recessed bolted clamps. In Puccio et al U.S. Pat. No. 4,339,214 the resilient seal is strengthened by the use of intermediate metal reinforcing inserts which laterally slide on a support beam and form the vehicle support surface.
The Barlow U.S. Pat. No. 4,129,967 expansion joint seal employs a tongue and groove securing arrangement that requires a slidable bridging plate for protecting the resilient seal element. The seal employs a tongue and groove arrangement that merely holds the protected seal.
The Hein et al U.S. Pat. No. 4,374,442 disclosed expansion joint requires an expensive and difficult to install convolution structure.
As described in the above identified prior art patents, which are hereby incorporated by this reference in full for any in all purpose as if fully set forth herein, the requirements of an expansion joint for service on roadway bridge decks, highways and the like are significantly more demanding than the requirements for simply sealing between essentially static structural panels and which are not subjected to the traction loading of tires in engagement with the expansion joint.
In general, the essentially static expansion joint seals not subjected to traction loading need only compensate in change of dimensions of the gap resulting from thermal variations. In such instances, it is relatively simple to use soft and resilient seal strips which may be received within securing channels on either side of the gap to be sealed. The resilient nature of the material coupled with the joint design are normally more than adequate to compensate for the thermal change in gap dimensions.
Roadway expansion joint seals must be either protected from the vehicular traffic or made sufficiently strong to resist, or withstand such loading. The corrosive effects of salt severly reduces the useful life of expansion joints employing metal protective shields or supports. In addition, the sliding arrangement of the metal components may also lead to premature failure in the event of binding. Employment of metal components in the expansion joint requires increased engineering planning and design, extensive preliminary fabrication efforts and a much heavier expansion joint which requires heavy equipment to handle and install.